Puerto Rico · County air quality · 2025
Bayamon County, Puerto Rico
Median AQI 29 (Good). 86.0% of monitored days rated Good, direct from EPA Air Quality System stations.
- 29
- Median AQI
- 86.0%
- Good-air days
- 0
- Unhealthy days
- 72%
- Cleaner than US counties
Bayamon County's 2025 annual median AQI is 29 (Good), with 86.0% Good days
According to the U.S. EPA Air Quality System, Bayamon County, Puerto Rico posted a 2025 median AQI of 29 (Good) across 164 monitored days, with 86.0% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Bayamon County's 86.0% Good-day share places it cleaner than 72% of US counties in 2025.
- Closest median-AQI peer
- Baker County (83.3% Good, median AQI 29) is the closest nationwide median-AQI peer to Bayamon County.
- 2020–2025 trend
- Bayamon County's floor-qualifying Good-day share is worsening from 2020 to 2025 (95.9% → 86.0%).
- Median AQI
- Median AQI: 29
According to the 2025 EPA AQS county release on PlainAirData, Bayamon County, Puerto Rico ranks #89 of 951 by median AQI (29) and #266 by good-day share (86.0%). Ponce County, Puerto Rico is #1 of 951 by median AQI (3, 91.4% Good days) at good-day-share #159 ≠ largest of 7 at 100.0% Good days #1 by good-day share (100.0%, median AQI 9) at median-AQI #7.
Annual release change
What changed in the 2025 EPA annual release
- Bayamon County's peak single-day AQI fell from 124 to 102 between the 2024 and 2025 EPA annual releases, a change of -22 points.
Data updated August 2026
- Good · 141 d · 86.0%
- Moderate · 21 d · 12.8%
- USG · 2 d · 1.2%
How did Bayamon County's air break down in 2025?
Across 164 monitored days, 141 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 102 (USG).
EPA AQS →Share of monitored days at AQI 0-50 (Good band).
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
Where Bayamon County sits nationally
COUNT-derived placement among 951 US counties with at least 100 monitored days in 2025. Bayamon County's Good-day share is 86.0% - cleaner than 72% of that comparison set.
Bayamon County Good-day share vs. every US county
Share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release
86.0% Cleaner than 72% higher than 72% of 951 US counties
Each bar is a band; taller bars hold more US counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Bayamon County.
- PM2.5 · 164 days · 100.0%
2024 daily-monitor rhythm in Bayamon County
Month-by-month median AQI from EPA day-level county monitors (314 reported days in 2024). Oct posted the highest typical readings (median AQI 36, peak 63); Nov was cleanest at median 22. Summer months (Jun–Aug) averaged median AQI 33 vs 27 in Dec–Feb.
Five-year seasonal record
EPA day-level county files · 2020–20241,505 daily readings show a recurring local pattern: May has the highest matched-month median AQI (24), while Aug is lowest (16). Each cell is that month’s median daily AQI, not a current-air forecast.
Lower AQI is better. The colors summarize EPA AQI bands; gaps mean the county had no day-level record for that month.
Health Impact Assessment
Bayamon County's air quality is rated Good based on 86.0% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 86.0% of monitored days in 2025, with a median AQI of 29. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 164 of 164 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Bayamon County. Highest Good-day share: 2020 (95.9%, 259 of 270 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 259 | 11 | 0 | 0 | 21 | 69 |
| 2021 | 320 | 27 | 0 | 0 | 10 | 77 |
| 2022 | 342 | 16 | 0 | 0 | 15 | 77 |
| 2023 | 193 | 23 | 0 | 0 | 22 | 74 |
| 2024 | 268 | 45 | 1 | 0 | 27 | 124 |
| 2025 | 141 | 21 | 2 | 0 | 29 | 102 |
How does Bayamon County compare?
How Bayamon County compares
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Bayamon County, Puerto Rico · 2020–2025
Download this county's annual AQI row as CSV , with the same EPA fields and denominator shown on this page.
Every figure on PlainAirData is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.